CVE-2018-10847 [Medium] | Authentication Bypass in Prosody

prosody before versions 0.10.2, 0.9.14 is vulnerable to an Authentication Bypass. Prosody did not verify that the virtual host associated with a user session remained the same across stream restarts. A user may authenticate to XMPP host A and migrate their authenticated session to XMPP host B of the same Prosody instance.

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-05-29	1.24%	0.26%	-0.97%
2	2026-02-13	1.30%	1.24%	-0.07%
3	2026-01-27	—	1.30%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-05-29

1.24%

0.26%

-0.97%

2026-02-13

1.30%

1.24%

-0.07%

2026-01-27

—

1.30%

—

Base score	Version	Severity	Vector	Exploitability	Impact	Score source
4.2	3.0	MEDIUM	`CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:H) Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:L) Some sensitive info could get out, but not a total data dump. Integrity (I:L) Attackers could change some data, but it’s limited—not everything goes. Availability (A:N) Service keeps running; no real outage angle.	1.6	2.5	[email protected]
8.8	3.0	HIGH	`CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H` Click to expand Attack vector (AV:N) Could be attacked over the internet or any normal routed network—not just someone sitting at the machine. Attack complexity (AC:L) Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup. Privileges required (PR:L) A normal user session is enough; they don’t have to be admin. User interaction (UI:N) Nobody has to click “OK” or open a trap file; it can work without a victim helping. Scope (S:U) Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems. Confidentiality (C:H) Serious risk that confidential data gets exposed in a big way. Integrity (I:H) They could widely tamper with or forge data—trust in the data is badly hurt. Availability (A:H) Could take the service down hard or make it unusable for people who depend on it.	2.8	5.9	[email protected]
6.5	2.0	MEDIUM	`AV:N/AC:L/Au:S/C:P/I:P/A:P` Click to expand Access vector (AV:N) Can be exploited remotely over network reachability. Access complexity (AC:L) Exploitation conditions are straightforward and predictable. Authentication (AU:S) A single authentication is required. Confidentiality impact (C:P) Partial confidentiality impact. Integrity impact (I:P) Partial integrity impact. Availability impact (A:P) Partial availability impact.	8.0	6.4	[email protected]

Base score

Version

Severity

Vector

Exploitability

Impact

Score source

4.2

3.0

MEDIUM

CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H): Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L): Some sensitive info could get out, but not a total data dump.
Integrity (I:L): Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N): Service keeps running; no real outage angle.

1.6

2.5

[email protected]

8.8

3.0

HIGH

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand

Attack vector (AV:N): Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L): Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L): A normal user session is enough; they don’t have to be admin.
User interaction (UI:N): Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U): Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H): Serious risk that confidential data gets exposed in a big way.
Integrity (I:H): They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H): Could take the service down hard or make it unusable for people who depend on it.

2.8

5.9

[email protected]

6.5

2.0

MEDIUM

AV:N/AC:L/Au:S/C:P/I:P/A:P Click to expand

Access vector (AV:N): Can be exploited remotely over network reachability.
Access complexity (AC:L): Exploitation conditions are straightforward and predictable.
Authentication (AU:S): A single authentication is required.
Confidentiality impact (C:P): Partial confidentiality impact.
Integrity impact (I:P): Partial integrity impact.
Availability impact (A:P): Partial availability impact.

8.0

6.4

[email protected]

OS Trackers for CVE-2018-10847

vendor	priority	summary	link
`debian`	not yet assigned	CVE-2018-10847 not yet assigned priority: Debian including 1 source packages (prosody), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5.	https://security-tracker.debian.org/tracker/CVE-2018-10847
`ubuntu`	low	CVE-2018-10847 low priority: Ubuntu including 1 source packages (prosody), 20 status rows across 20 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 15, released 2, DNE 1, needed 1, needs-triage 1.	https://ubuntu.com/security/CVE-2018-10847

Affected software / configurations for CVE-2018-10847

Vendor	Product	Version	Raw CPE
prosody	prosody	< 0.9.14	cpe:2.3:a:prosody:prosody::::::::
prosody	prosody	0.10.0	cpe:2.3:a:prosody:prosody:0.10.0:::::::*
prosody	prosody	0.10.1	cpe:2.3:a:prosody:prosody:0.10.1:::::::*

References for CVE-2018-10847

URL	Tags
https://blog.prosody.im/prosody-0-10-2-security-release/	Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-10847	Issue Tracking Third Party Advisory
https://issues.prosody.im/1147	Vendor Advisory
https://prosody.im/security/advisory_20180531/	Vendor Advisory
https://www.debian.org/security/2018/dsa-4216	Third Party Advisory

URL

CVE-2018-10847

Exploit prediction scoring system (EPSS) score for CVE-2018-10847

Common vulnerability scoring system (CVSS) metrics for CVE-2018-10847

Weakness enumeration for CVE-2018-10847

OS Trackers for CVE-2018-10847

Affected software / configurations for CVE-2018-10847

References for CVE-2018-10847